As an additional cost to cast this spell, sacrifice a creature.

Return a creature card from your graveyard to the battlefield, then return another creature card from your graveyard to your hand.

Flying

Threshold — As long as seven or more cards are in your graveyard, Boneshard Slasher gets +2/+2 and has "When Boneshard Slasher becomes the target of a spell or ability, sacrifice it."

All Sliver creatures get +2/+0.

Wither (This deals damage to creatures in the form of -1/-1 counters.)

: Regenerate Cinderbones.

: Prevent the next 3 damage that would be dealt to target creature this turn. Activate only if you have more cards in hand than each opponent.

, Reveal X black cards from your hand, Sacrifice Martyr of Bones: Exile up to X target cards from a single graveyard.

Haste

Tribute 2 (As this creature enters the battlefield, an opponent of your choice may put two +1/+1 counters on it.)

When Oracle of Bones enters the battlefield, if tribute wasn't paid, you may cast an instant or sorcery spell from your hand without paying its mana cost.

, : Target creature gains swampwalk until end of turn. (It can't be blocked as long as defending player controls a Swamp.)

: Regenerate Restless Bones.

Deathtouch

Whenever Tinybones, the Pickpocket deals combat damage to a player, you may cast target nonland permanent card from that player's graveyard, and mana of any type can be spent to cast that spell.

Each opponent who controls more creatures than you can't cast creature spells. The same is true for artifacts and enchantments.

Each opponent who controls more lands than you can't play lands.